In vehicle engines, it is sometimes desirable to meter incremental amounts of oil from the engine for oil recovery, filtration of dirty oil, burn off of dirty oil, oil makeup, specialized lubrication, etc. Such oil management systems require metering devices which are separate from the oil pump, which results in increased costs, increased weight, and increased packaging space requirements. Such an oil management metering device would typically require a pump or other pressure source, a pulley or pump motor for driving the pump, various hydraulic lines and valves, as well as sufficient packaging space within the engine compartment for storage.
One example of such a system is U.S. Pat. No. 4,495,909, which requires two solenoids, a hydraulic cylinder and a source of pressurized air, as well as numerous valves and ports, to accomplish the oil removal. Similarly, U.S. Pat. No. 4,421,078 requires three solenoid valves, a source of pressurized air, an air/oil cylinder, a piston and various vents, fittings and ports for oil removal.
Accordingly, it is desirable to provide an improved oil management metering device which does not require an additional pump or motor and which uses minimal engine compartment space.